This story was excerpted from Jordan Bastian¡¯s Cubs Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

The first act of?top prospect Pete Crow-Armstrong¡¯s?career with the Cubs was to don a helmet and hustle to first base as a pinch-runner in the seventh inning on Monday night. Up on the massive Coors Field scoreboard, the rookie outfielder was introduced into the displayed lineup simply as, ¡°Unknown PR.¡±

¡°That¡¯s hilarious,¡± Crow-Armstrong said with a smile. ¡°That¡¯s good stuff.¡±

Coors Field was packed with plenty of well-versed Cubs fans, who made sure people learned quickly about this ¡°unknown¡± runner. When the center fielder stepped to the plate for his first MLB at-bat in the ninth, alternating chants of, ¡°P-C-A!¡± and ¡°Let¡¯s go, Pete!¡± broke out in different sections.

Crow-Armstrong showed exactly who he is -- and why the Cubs summoned him to the big leagues -- with?a pair of spectacular catches on Tuesday night. MLB Pipeline¡¯s?No. 12-ranked prospect?has 80-grade defense and plus speed, which are traits that could help Chicago in the last two weeks, and potentially in October.

That said, the 21-year-old Crow-Armstrong is not a finished project.

¡°There's teachable moments,¡± Cubs manager?David Ross?said. ¡°There's things he's got to follow and understand, a process that we have here that is important. And prospect baseball is different than winning baseball, right? He's got to learn that. He¡¯s coming into a group that we're willing to help him out as a coaching staff, and as his teammates, because he's very valuable.¡±

Some teachable moments did arrive early, too.

In Monday¡¯s win, Crow-Armstrong was thrown out trying to steal third base by one of the better defensive catchers in baseball in Colorado¡¯s?Elias Diaz. On Tuesday, Diaz nabbed the rookie at second base after he tried to move up on a ball in the dirt. Wednesday¡¯s loss featured a sacrifice bunt gone wrong and a fly ball lost in the tough Colorado sky. The rookie went 0-for-7 in his first three games.

¡°Rookie mistakes are a real thing. I made them, too,¡± Cubs center fielder?Cody Bellinger?said. ¡°The best way to learn is to kind of make those mistakes. For me, I was up in April my first year, so I had a whole season. He's up in the middle of September. It's a little different.

¡°But he understands that we're all here rooting for him and we're all here pulling for him. And the guidance is there to help him through situations.¡±

Crow-Armstrong has already been diving into conversations with third-base and outfield coach?Willie Harris?and first-base coach?Mike Napoli. Harris, in particular, has been reaching out to the outfielder for the past few months, shooting him encouraging text messages and bits of advice.

One of Harris¡¯ messages to a hyper-competitive kid who plays full throttle has been to know when to slow down.

¡°If you've already worked on slowing things down,¡± Harris said, ¡°when you get here, the game doesn't speed up on you. He¡¯s got sick ability --?sick?ability. He just made me one of the best outfield coaches in baseball. I¡¯m looking forward to watching him play, excited that he¡¯s here and getting a chance to live out his dream.

¡°And I¡¯ll be here to support him -- someone he can lean on. He can dive into me for whatever he needs and I¡¯ll stay out of his way and let him do his thing. But when it¡¯s time to work, we¡¯ll work.¡±

Crow-Armstrong has already appreciated that approach.

¡°I've always loved how the organization has vocalized their plans for certain players,¡± he said. ¡°And yeah, I just really appreciate the faith they've had in me and the trust they've had in me -- enough trust to go out and play center field in a playoff race. ¡­ However I can help and however I can learn is what I¡¯m trying to get out of this.¡±